Certain conditions and diseases of the eye, such as corneal failure, keratoconus, corneal dystrophies, scarring, age related macular degeneration (AMD) and retinitis pigmentosa, have been treated using ocular transplant procedures such as corneal and retinal pigment epithelial (RPE) transplants. Transplant rejection is one of the problems which may arise from transplant procedures (Enzmann V et al. (1998). “Immunological problems of transplantation into the subretinal space.” Acta Anat (Basel). 162(2-3): 178-83). In spite of the overall success with corneal transplants, a substantial percentage of corneal grafts experience at least one rejection episode (PCT/US97/21393).
One of the problems with present immunosuppressive drug therapy is the inability to achieve adequate intraocular drug concentrations. Systemic immunosuppression may require prolonged exposure to high plasma concentrations so that therapeutic levels can be achieved in the eye. Overall drug delivery to the eye may be poor due to the short drug plasma half-life limiting exposure into intraocular tissues. In addition, this may in turn lead to numerous negative side effects.
There is a continued need for improved intraocular sustained release drug therapies for patients following ocular transplant procedures.
All references cited in this patent are incorporated herein by reference in their entirety.